The present invention provides a detectable heavy duty needle cannula (12) for use in hypodermic syringes and the like. Needle cannula (12) comprises a magnetizable or magnetized stainless steel alloy, which enables needle cannula (12) to be detectable in metal detectors that are commonly used in the meat processing industry to detect broken needle cannulas in the flesh of slaughtered animals. Needle cannula (12) further comprises a sidewall (17) that is thicker than the sidewalls of prior art needle cannulas. The thicker sidewall imparts to needle cannula (12) greater resistance to breakage during the process of injecting animal health products into an animal and greater detectability in a metal detector.